The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 30, 1999
Filed:
Oct. 15, 1997
Fuji Photo Optical Co., Ltd., Omiya, JP;
Abstract
In an optical pickup apparatus which can be commonly used for a plurality of optical disks having different thickness values, thickness t of a optical transparent plane plate for thickness compensation is set by means of skew ray formula so that the amount of spherical aberration caused by the optical system is lowered, thus allowing accurate focusing for each of a plurality of optical disks having different thickness values. Spherical aberration S.A. is given by expression of S.A..ident.S'.sub.k -S'.sub.k0, wherein S'.sub.k is computed by expression of S'.sub.k =Ax.sub.k -(X'.sub.k /Y'.sub.k)Ay.sub.k. Here, by setting S'.sub.k -S'.sub.k0 =minimal value, the geometric thickness of the plane plate 8 can be determined.